Department of Energy Conversion and Storage, Technical University of Denmark, DTU Risø Campus, DK-4000 Roskilde, Denmark.
Center for Electron Nanoscopy, Technical University of Denmark Lyngby Campus, DK-2800 Kgs. Lyngby, Denmark.
Nat Mater. 2015 May;14(5):500-4. doi: 10.1038/nmat4266. Epub 2015 Apr 13.
Bismuth-oxide-based materials are the building blocks for modern ferroelectrics, multiferroics, gas sensors, light photocatalysts and fuel cells. Although the cubic fluorite δ-phase of bismuth oxide (δ-Bi2O3) exhibits the highest conductivity of known solid-state oxygen ion conductors, its instability prevents use at low temperature. Here we demonstrate the possibility of stabilizing δ-Bi2O3 using highly coherent interfaces of alternating layers of Er2O3-stabilized δ-Bi2O3 and Gd2O3-doped CeO2. Remarkably, an exceptionally high chemical stability in reducing conditions and redox cycles at high temperature, usually unattainable for Bi2O3-based materials, is achieved. Even more interestingly, at low oxygen partial pressure the layered material shows anomalous high conductivity, equal or superior to pure δ-Bi2O3 in air. This suggests a strategy to design and stabilize new materials that are comprised of intrinsically unstable but high-performing component materials.
基于氧化铋的材料是现代铁电体、多铁体、气体传感器、光催化剂和燃料电池的基础。尽管氧化铋的立方萤石 δ 相（δ-Bi2O3）表现出已知固态氧离子导体中最高的电导率，但由于其不稳定性，无法在低温下使用。在这里，我们证明了使用 Er2O3 稳定的 δ-Bi2O3 和 Gd2O3 掺杂的 CeO2 交替层的高度相干界面稳定 δ-Bi2O3 的可能性。值得注意的是，即使在高温下进行还原条件和氧化还原循环，也能实现通常无法实现的 Bi2O3 基材料的异常高化学稳定性。更有趣的是，在低氧分压下，层状材料表现出异常高的电导率，在空气中与纯 δ-Bi2O3 相等或更高。这表明了一种设计和稳定新材料的策略，这些新材料由固有不稳定但性能较高的组成材料组成。
